Numerous medical diagnostic and interventional procedures involve the use of long catheters which are placed within the human vascular system. These catheters are delivered over guide wires to positions in the heart for cardiac procedures and into the brain for neurological procedures. The point of entry is normally a puncture hole in the femoral artery in the patient's groin. Once the procedure has been completed the catheter and guide wire are removed and the puncture hole must be closed in order to prevent excessive bleeding and the possibility of infection. Traditionally this puncture hole has been closed by maintaining manual pressure at the puncture site until homeostasis occurs around the puncture hole or placing sand bags on an area of the groin close to the puncture hole and keeping the patient immobilised until homeostasis occurs.
In recent times a number of medical devices have been developed and marketed for the purpose of closing this puncture hole. These devices fall broadly into two categories (a) mechanical closure devices such as those which use sutures or staples to mechanically close the puncture hole, and (b) occlusion devices such as collagen plugs and gels. Examples of prior art in this area include U.S. Pat. Nos. 5,860,991 and 6,322,580.
U.S. Pat. No. 5,860,991 describes a device for closing puncture holes utilizing a suture. The device is positioned into the artery over the guide wire until a blood signal appears at the proximal end indicating proper position has been attained. At this point an internal anchor is deployed and needles are advanced from outside the artery, through the arterial wall and into the anchor component to grab opposite ends of a suture loop. The needles are then retracted back into the device and the device is removed from the artery leaving the open ends of the suture external on the patients skin. A knot is tied and run down the suture tightening the loop around the puncture hole and closing it. A cutter device is then used to cut the suture.
The problems associated with this device are the significant number of steps in its use, tying of the suture loop involves a sawing action around the puncture hole which could unintentionally cause the suture to cut its way through the hole, pushing needles from outside the artery to inside creates two additional puncture holes and finally a loop of suture remains inside the artery and has the potential to dislodge plaque within the artery.
Another example of a mechanical closure device is described in U.S. Pat. No. 6,322,580 which uses a metallic staple to close the puncture hole. This device involves the use of a special dilator and sheath which are guided into the femoral artery over a guide wire. Once the guide wire is removed internal stabilizers are activated and retracted against the internal wall of the artery. The sheath dilator is then removed and a stapler device is advanced through the sheath and the staple deployed into the arterial wall. The stapler is then removed, the stabilisers deactivated and the introducer sheath removed from the tissue tract.
Problems associated with this device include the use of a specialised sheath which must be inserted over the guide wire and advanced into the tissue tract before the closure procedure can take place. In addition delicate stabiliser type devices must be deployed within the artery before the stapler can be delivered to close the puncture hole. Once the staple is delivered the staple device is removed from the sheath, the internal stabilisers are then collapsed and retracted through the puncture hole and into the sheath before the sheath itself can be removed from the tissue tract.
While both devices described above are effective in terms of closing puncture holes they are mechanically complex in nature in terms of operation. In addition a significant number of steps are involved in the procedure. The end users of such devices are more familiar with catheter-based technologies delivered over guide wires, combined with the inflation and deflation of balloons. Therefore there is a need for an improved puncture closure device which operates in a manner more consistent with catheter based devices such as angiography and angioplasty catheters. In addition there is a need to reduce the complexity of such devices by reducing the number of components involved and the number of steps involved in the procedure.